This invention relates to lasers and particularly to molecular iodine lasers that emit in the near infrared range.
There has been considerable recent interest in both atomic and molecular iodine lasers in the past few years. Optically pumped iodine lasers have been investigated and reported in the literature. Iodine lasers offer tunable output from approximately 544 to 1350 nm and have been operated in both pulse and continuous wave (cw) modes of operation.
Although the iodine molecule (I.sub.2) is one of the most thoroughly studied diatomic species with numerous spectroscopic and data studies available, amplified spontaneous emission of iodine (B.fwdarw.X) has only recently been studied in detail. In our paper entitled "Multilevel Cooperative Amplified Spontaneous Emission from the I.sub.2 (B.fwdarw.X) System" published in the Journal of Applied Physics, vol 62 (1), 1 July 1987 we reported our most recent experiments with amplified spontaneous emission (ASE) in iodine (I.sub.2). These experiments utilize a YAG-laser pumped dye laser system as an excitation source for an iodine filled cell. Amplified spontaneous emission (ASE) was detected and measured in the near infrared spectra from the iodine cell. Unfortunately, the quantum efficiency of ASE conversion was only in the area of 1 percent.
An iodine ASE device could prove to be a simple and efficient frequency shifter for a pulsed dye laser if the ASE quantum efficiency could be improved. Since the emission occurs in the spectral range of 1.0-1.34 microns, such a device could compete with hydrogen-Raman shifters. Higher efficiencies for the conversion of visible dye laser photons to near infrared photons would make the device an important tool for spectroscopic studies including chemical analysis and meteorology.
An iodine ASE device would be much less expensive to manufacture and easier to use than the conventional hydrogen-Raman shifters. This is because hydrogen shifters require high pressure steel containment cells with thick windows. Unfortunately, the iodine device which we have studied in the above- referenced paper was not capable of emitting sufficient energy to be a useful tool.
A need therefore exists for an improved iodine ASE laser capable of extended pulsed or continuous wave (CW) operation at sufficient power to be a useful spectroscopy tool.
A need also exists for a low cost tunable iodine laser which does not require expensive high precision components.